Preparation

Combine milk, 1/2 cup cream, sugar, salt,
and 1/4 cup water in a large heavy saucepan.
Scrape in seeds from vanilla bean; add
bean. Bring to a boil, stirring to dissolve
sugar. Add chocolate and cocoa powder;
whisk until chocolate melts and mixture just
comes to a boil. DO AHEAD: Cocoa can be
made 1 day ahead. Let cool; cover and chill.
Bring to a simmer before continuing.

Whisk remaining 1/2 cup cream and
ground coffee in a small bowl until firm
peaks form. DO AHEAD: Whipped cream can
be made 2 hours ahead. Cover and chill.
Rewhisk if needed before using.

Remove vanilla bean from hot cocoa;
discard. Transfer cocoa to a blender and
purée until thick and foamy, about 2 minutes.

Scoop ice cream into teacups; pour hot
cocoa into cups, dividing evenly. Top each
with a small dollop of coffee whipped cream.
Garnish with a small candy cane, if desired.